The overall goal of this project is to evaluate the use of proton NMR spectroscopic imaging (1H-MRSI) as a surrogate marker to non-invasively detect residual tumor after non-adjuvant androgen ablation + chemotherapy and to assess the effectiveness of chemotherapy in prostate cancer. The specific aims of the study are: 1. To determine whether the data from pre-treatment 1H-MRSI of the prostate correlates with neo-adjuvant hormone+chemotherapy outcome as measured by the presence and extent of residual disease in surgical specimens. 2. To determine whether the 1H MRSI data at the chemotherapy midpoint (2 months) or changes in this data between the baseline and 2 months can predict the presence and extent of residual disease after 4 months of treatment with chemotherapy+hormone therapy. 3. To determine whether the 1H-MRSI data after four months of chemotherapy+hormone therapy predicts the presence and extent of residual disease at surgery. The subjects of the study are prostate cancer patients who have clinically localized prostate cancer at diagnosis, but are considered to have a high risk of recurrence after surgery or radiotherapy alone based on elevated PSA and/or Gleason grade. These patients are taking part in a clinical trial of neo-adjuvant androgen ablation plus chemotherapy with the hope of improving prognosis after surgery or radiotherapy. MRI and 1H-MRSI employing an endorectal probe will be performed on consenting patients on three occasions: (1) prior to neo-adjuvant hormone+chemotherapy, (2) at the midpoint of the treatment and (3) at the end of the treatment. Choline, creatine, and citrate will be mapped at 6.1 mm spatial resolution in order to assess the presence and extent of cancer. 1H-MRSI results will be compared to step-section histopathology of surgically resected prostate specimens. Significance Prostate cancer is common and unpredictable. Because of the location of the prostate gland, and the morbidity associated with its surgical removal (urinary incontinence, impotence) alternatives to surgical removal are of great practical significance to the practice of urology in males. PSA measurements have allowed early diagnosis, but staging of the disease and predicting the few disastrous cases (as compared to the many indolent cases) remains a major challenge comparable to early detection and cure of breast cancer in women.